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Carcharhinus tilstoni
Carcharhinus tilstoni (''Australian blacktip shark)' Kingdom: '''Animalia Phylum: Chordata Class: Chondrichthyes Order: Carcharhiniformes Family: Carcharhinidae Genus: Carcharhinus Species: Carcharhinus tilstoni Environment: milieu, climate zone, depth range, distribution range: Marine; brackish; pelagic-neritic; depth range 0 - 150 m. Tropical; 10°S - 28°S. Distribution: Indo-West Pacific: currently known only from the continental shelf of tropical Australia. Very similar to Carcharhinus limbatus and reliably distinguished only by biochemical studies and vertebral counts. Size, weight, age: Max. length: 2 m; weight: 52 kg; age: 12 years Short description: Physically, the Australian blacktip shark can only reliably be distinguished from the common blacktip shark by the number of vertebrae (174–182 total, 84–91 before the tail in C. tilstoni, 182–203 total, 94–102 before the tail in C. limbatus). It has a moderately robust, spindle-shaped body and a long, pointed snout. The anterior rims of the nostrils are slightly enlarged into low triangular flaps. The large, circular eyes are equipped with nictitating membranes. The furrows at the corners of the mouth are barely evident. There are 32–35 upper and 29–31 lower tooth rows; each upper tooth has a slender, upright cusp and fine serrations that become coarser near the base, while the lower teeth are narrower and more finely serrated. The five pairs of gill slits are long. The long and narrow pectoral fins are falcate (sickle-shaped) with pointed tips. The large first dorsal fin is also falcate and originates over or slightly behind the rear of the pectoral fin bases. The second dorsal fin is moderately tall and positioned about opposite the anal fin. There is no midline ridge between the dorsal fins. A crescent-shaped notch is present on the caudal peduncle just before the upper caudal fin origin. The caudal fin is asymmetrical, with a strong lower lobe and a longer upper lobe with a ventral notch near the tip. The roughly diamond-shaped dermal denticles are placed closely together and slightly overlapping; each bears five to seven (three in juveniles) horizontal ridges leading to marginal teeth. The Australian blacktip shark is bronze above (gray after death) and whitish below, with a pale stripe on the flanks. Some individuals have black tips on all fins, while others have unmarked pelvic and anal fins. It typically reaches 1.5–1.8 m (4.9–5.9 ft) long; the maximum length and weight on record are 2.0 m (6.6 ft) and 52 kg (115 lb). Biology: Found on the continental shelf from close inshore to about 150 m depth. Found throughout the water column but usually near the sea bed during the day and near the surface at night. Prefers teleost fishes but also feeds on cephalopods to a lesser degree. Viviparous. Forms large aggregations. Utilized for its meat and fins. The flesh has a relatively high mercury content. Life cycle and mating behavior: Viviparous, placental. The average litter size is 3, with a range of 1-6, average total length at birth is 60 cm. Pups are born in January after a 10-month gestation period. These sharks breed once each year. Distinct pairing with embrace. Main reference: Kailola, P.J., M.J. Williams, P.C. Stewart, R.E. Reichelt, A. McNee and C. Grieve, 1993. Australian fisheries resources. Bureau of Resource Sciences, Canberra, Australia. 422 p. IUCN Red List Status: LEAST CONCERN (''LC)' '''CITES: Not Evaluated CMS: Not Evaluated Threat to humans: Harmless Human uses: Fisheries: minor commercial. Category:Carcharhinidae, Sharks